Technical Field
The present invention relates to a material for manufacturing contact lenses. More particularly, the contact lenses made from a hydrophilic siloxane macromer and a surfactant have high water content, high oxygen permeability and low modulus.
Description of Related Art
In the early years, hard contact lenses were mainly made of glass. The soft contact lenses were therefore developed to improve discomfort of wearing of hard contact lenses. The soft contact lenses can be classified into two categories, hydrogel contact lenses and silicone hydrogel contact lenses.
The hydrogel contact lenses are made from hydrogel materials such as poly-2-hydroxyethyl methacrylate (p-HEMA). Since the limited material characteristics of hydrogel contact lenses, the oxygen permeability (Dk) thereof is only about 15 to 35.
Comparing to the hydrogel contact lenses, the silicone hydrogel contact lenses have higher oxygen permeability because they are made from siloxane macromer and hydrophilic monomers. Although the siloxane macromer structure is able to provide high oxygen permeability, the lower water content and the higher tensile modulus thereof are caused at the same time. If the water content of the contact lens is too low, the wear's eyes will be too dry to induce discomfort. If the tensile modulus of the contact lens is too high, the contact lens-induced conjunctival straining (C.L.I.C.S) of wearers is caused easily. Moreover, if the wearers wear the contact lenses in a wrong way, the sickness of eyes may occur more easily. Therefore, a novel material for manufacturing contact lenses is highly demanded to solve the aforementioned problems.